PAKISTAN CLOUD FIRST POLICY Annex A – Cloud Service Models Cloud computing is available in three different service models. Each of these service models fulfils a unique set of business requirements. Following are the three service models of cloud computing. 12.1 Software as a Service (SaaS) PSE can use the provider’s applications running on cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser. PSE does not manage or control the underlying cloud infrastructure. Examples of use include accounting, email, and document management tools. 12.2 Platform as a Service (PaaS) The cloud infrastructure is PSE-created or PSE acquired applications created using programming languages and tools supported by the provider. The PSE does not manage or control the underlying cloud infrastructure including networking, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations. Examples include databases, programming environments, and video teleconferencing tools. 12.3 Infrastructure as a Service (IaaS) PSE can provision processing, storage, networks, and other fundamental computing resources where the PSE can deploy and run arbitrary software, which can include operating systems and applications. PSE does not manage or control the underlying cloud infrastructure, but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (such as host firewalls). Examples include networking storage and virtualisation servers. Page 16 of 21